Abstract: A filtration system for an aquarium having water and fish. A container is mounted in juxtaposition to the aquarium and a porous filter is disposed in the container. The top of the filter is connected to the bottom of a pot in which is growing a terrestrial plant in soil. A pump circulates water from the aquarium into the container and through the filter. The filter removes solid and dissolved pollutants from the water and roots of the plant grow into the filter, utilizing the pollutants retained in the filter.